Attacking a school, or any other innocent population, then the Muslim French would be opposed to them, would publicly denounce the atrocity, and would potentially suffer any backlash as a misunderstanding. By attacking a satirical paper that is critical of Islam, at least some of the Muslim French would be sympathizers. Any backlash against Muslims in general would then work towards radicalizing the sympathizers, drawing them to the cause.
Attacking a school, or any other innocent population, then the Muslim French would be opposed to them, would publicly denounce the atrocity, and would potentially suffer any backlash as a misunderstanding. By attacking a satirical paper that is critical of Islam, at least some of the Muslim French would be sympathizers. Any backlash against Muslims in general would then work towards radicalizing the sympathizers, drawing them to the cause.